I would like a pack bait or method mix that I could cast out over 100 yards and stay on until it hits the bottom of lake and starts to break down within 5 mins.

When I try experimenting I either get a mix that breaks away on cast or doesn't break down for hours.

Any help with ideas for good binders that might break down in the water after a few minutes would be great.

try this one out, has worked well for me

rabbit pellets, cracked corn, layer mash crumble or pellets, bread crumb.

to make a 5 gallon bucket

4 cups layer mash
2 cups rabbit pellets
2 cups cracked corn
mix dry in bucket.

get another bucket put 4 cups of dry method, add a can of bread crumb, a lot of chilli powder, if you want to add oats you can or grits, 1 cup of ethier, and 1 to 1 1/2 cups of water. mix till sticky let sit for a couple minutes, then mix again and should be nice and tacky ready to use